I have a 2000 tahoe lt with onstar and factory sub and amp, without bose. i have figured out the standard door speakers as 6.5" and replaced them with These Skar Audio Speakers from amazon and plan to do the same with the rear doors. I plan to get this sub and amp setup from skar audio. I havent done anything with the rear pillar tweeters or the factory subwoofer. I have thought of replacing the factory sub with this 8" woofer from skar but dont know about the depth or which ohm to go with. The only ones i cant get my head around are the front door tweeters. Factory GM number is 15204326. Preferably looking for a drop in replacement from a reputable brand. Also the rear pillar tweeters, I haven't even looked at those ones though.